1. Field of the Invention
The present invention relates to a distal end structure of an endoscope in which a single use cover is attached to a distal end member provided at an endoscope distal end.
2. Description of the Related Art
There has been known an endoscope in which a high-frequency treatment instrument is used. The endoscope of this type has a structure in which, in order to safely use the high-frequency treatment instrument, a surface of an elongated insertion section is coated with an insulative resin material, an insulative rubber member is further disposed in an exterior portion of a bending section disposed on a distal end side of the insertion section, and a cover formed of an insulative material is attached to a distal end portion to insulate the entire insertion section of the endoscope. By attaching the cover, when an insertion section distal end is inserted into a bent body cavity of a human body or the like, even if the insertion section distal end touches a body cavity inner wall, it is possible to protect the body cavity inner wall from damage.
When safety is taken into account, the cover is desirably fixed to the distal end portion by an adhesive. However, the endoscope needs to be sufficiently cleaned and disinfected after use. For example, when a mechanical component such as a raising base for raising a treatment instrument is housed in the distal end portion, gaps among respective components are narrow and cleaning work takes time.
Therefore, for example, there has been known an endoscope in which a cover is enabled to be attached and detached, in cleaning and disinfection, the cover is detached from a distal end portion to make it easy to clean both of the cover and the distal end portion, and the cover can be attached to the distal end portion after the cleaning.
However, for a reusable cover, complicated work for, for example, pushing in the cover while rotating in reattachment is requested to prevent the cover from coming off or positionally deviating during use. There is also a problem in that material characteristics change because of repeated use of the cover.
As measures against this problem, for example, Japanese Patent Application Laid-Open Publication No. 2007-289434 proposes a technique for attaching a single use cover to a distal end portion. That is, in the cover disclosed in the patent literature, a finger hook section is provided on one side. The finger hook section is pinched and pulled by fingers to tear off a thin portion and a recessed groove formed near the finger hook section to detach the cover from the distal end portion.
The cover disclosed in the patent literature is configured such that a groove section is formed on an inner surface in order to prevent the cover from coming off a distal end portion after attachment, the groove section is engaged with a locking section formed at the distal end portion, and, when the thin portion is torn off from the cover, the groove section and the locking section are disengaged.